Roller coating machine for rigid sheet material



June 16, 1953 BRINK 2,642,030

ROLLER COATING MACHINE FOR RIGID SHEET MATERIAL Filed July 28, 1949 3 Sheets-Sheet l INVENTOR sow/1v H- BKI K BY a/m w ATTORN EY E. H. BRlNK June 16, 1953 ROLLER COATING MACHINE FOR RIGID SHEET MATERIAL '3 Sheets-Sheet 2 Filed July 28, 1949 INVENTOR R E B m a m .Y 4 Wm p E k E. H. BRINK June 16, 1953 ROLLER COATING MACHINE FOR RIGID SHEET MATERIAL 3 Sheets-Sheet 3 Filed July 28, 1949 INVENTOR ATTORNEY Patented June 16, 1953 :ROLLER' COATING MACHINE -FOR' RIGID SHEET MATERIAL *Edwin H. Brink, Laurelf-Mis's as'signo'r "to '-Masonite corp'oration, Laurel, Mis's., a; corpol ation of Delaware I Applica tion JulylZS, 1949, SeriaI Nm- IOTJKI S 'CIai-ms.

V Ihis invention ri-ilatesto roll coatin'g'machines =and more .i'particularly "to a roll coating mach ne I which permits applioati'onof "a smooth T coating of uniform appearance on thesurface'of a rigid sheet material having'su'rface imperfections. "By

rigid is meant sheet materials having sub- --stantia1 thickness and rigidity as distinguished :from' paper andt'he like. I

There has been a long-felt but heretofore unfi lled need for the type roll coating ma'chine of the pr sent invention which enables the application of a smooth coating of a uniform appearance to -the'surface of :a'rigid'shee't material in "spite of surface 'imperfection'siof' the sheet such ase.i g.

roughness in combination with nonuniform caliper. I II I I r I 7 Some types of sheet materials have-such 'su'rface imperfections as a characteristiofeature.

, There are othertypes ofisheet materials which are not ordinarily characterized by these imp'e'rfections; but occasi'onally do have'thes'e or similar imperfections to such an extentthatthey cannot be-given a smooth coating of uniform'appearance "by means of prior artcoatirig-machines. Examples of such sheets are I {made in accordance withpate'nts such as U. S. 'Patents 1,663,505 and 2,120,137. 50 far'asknown, none of' the roll coating machinesofthe prior arthave-provisionfor obtaining a smooth coatfaces of such sheet materials.

-An object of the present in'ven'tion'is to pro- "viae a 011 coating machine which enables the application of a coating material to the surface of a rigid sheet material, the finish coat'being smooth and of uniform appearance. Another object is to providea'roll coating machine which enables the application of a coacting material to thesurface of arigid'sheet material having surface imperfections, the finish coat'bei'ng-smooth and-'of'uniform appearance. A further object is to provide a roll coating machine which makes pes'sible'the'appheauenbf a coating materiarto 'I'the'sur'f ace o'fa'ri'gid sheet material having rough surfaces and nonuniform caliper, the fini sh -coat "bemgsmeothend of uniform alp'pearance. --A i 'stillifurtherobjective-is to provide a; roll coating "machine which makes "possible the application of a coating material "to a' rigid sheet 'material,

having "a combination of'rou'gh suiraee-ana nonfunifor'm caliper, 'in a manner that effectively "counteracts thepaliper Variations while permitting filling onl y lthe 'lowI places' 'in' the rough asurff 'e. ther. oloj'ec illi'te apparent. ream the description ofthis' invefitin "'given' hei' eir'ia'ftr.

Masonite hardboards Q ing of uniform appearance ontheimperfectsur- "'2 -TI-1'e above objects are accomplished according 't'o this "invention by ,Iproviding and employing 'a roll coating apparatus 'comprisingm'eans for'a'p- 'i lyiriganexcess of coating material to the,

'fa ce'of the material to becoated; a wiping roll fixedly journaled'; a pressure'roll opposed to and cooperating with said Wiping roll, the'axesof the two rolls being substantially parallel and in a "plane" substantially perpendicular 'to that surf ace of the material beingicoate'd, at leastithe outer portion of the pressure "roll being'of .a resilient material surrounding the roll, the pressure roll being'so 'journaled'as' to be'yieldable in said plane and to exert a substantially constant and'uniform pressure; and means for removingtheexcess of coating material fromf the wiping roll.

A preferred' embodiment"of this invention will "now be described inmo're detail with reference to the accompanying drawing. Like reference numeralsare usedto indicate identical parts.

'Referr'ingtothe drawing generally:

Figure l is a'""side elevation 'inpa'rtial section showing "an apparatus embodying the general aspects 'dfth'e invention. I Figure 2 is a cross section view along the line 2-2 of Figure 1 "of 1a 'hard'board in which the imperfections "of rough surface and nonuniform c'alip'erare greatly exaggerated to assist. inxthe understanding of the invention.

Figure 31s a, crosssecti'on view along the line 3-3 fof"Fi'gure 1 "(coating materialon the hardbojard not shown) I Figure 4"isfa'c'r'o's's sectionwiew along the line 4-4 of "Figure "2.

Figure 5' is aside elevation showing the pres- "sure' rolls m'ount'edxon 'fiuidsupported pistons as mounted around ""a relatively nonresilient. core 3 a paint supply trough i; a coating appli'cator roll i'so disposed *astoprovideonesideof trough 3 the surface of which applicator roll is adapted (such as circumferentially grooved surface 6) to pick up coating material, e. g. paint, from the pain supply trough and apply it to that surface I of the board 8 being coated; a doctor roll 9 having its axis parallel to and adjustable (as indicated by arrows A) with respect to distance from the axis of the applicator roll, which applicator roll is so disposed as to provide the second side of trough 4; members IQ for closing the ends of trough l; a smooth hard polished surface wiping roll II; means 25 for driving the wiping roll at a predetermined differential surface speed and in a reverse direction relative to that of the board being coated; a doctor blade I2, the drive roll I and applicator roll 5 and wiping roll I I being fixedly journaled; work supporting pressure rolls I3, I 4 and I5 opposed to and cooperating with the drive roll I and applicator roll 5 and wiping roll II, respectively, the axis of each pair of said rolls being parallel and in a plane perpendicular to that surface 1! of the board 8 being coated, the

outer portion 2 of each of said pressure rolls being of a resilient material such as rubber in the form of a sleeve 2 surrounding the roll, each of the pressure rolls being journaled in a journal box which in turn is mounted on a spring I6 so that each pressure roll is yieldable (as indicated by arrows B) in a plane perpendicular to that surface I of the board 8 being coated; setscrews I! for adjusting the compression of the springs It; and stops (not shown) to prevent the pressure rolls from contacting their respective opposing rolls in the absence of a sheet material therebetween.

The operation of the above described coating machine now will be further described with reference to coating hardboard. Although this roll coating machine is applicable to coating sheet materials in general, the unusual features of the machine are more fully utilized in coating sheet materials (e. g. hardboards, wallboards, plywood and the like) having surface and caliper variations, and particularly those variations pointed out herein.

Figures 2 and 4 show the surface imperfections encountered in hardboards. These typical imperfections are exaggerated in the drawings to assist in the understanding of the invention. As will be seen from these figures, the caliper of the board varies from side to side and also from end to end, i. e. across the machine direction as well as with the machine direction. Generally the caliper at the center of hardboards is low and the caliper at the edges is high with a gradual substantially uniform change in caliper between low and high caliper. Caliper variations are usually in the order of about .01.02 inch. From these figures it will also be seen that the surfaces of the board have a series of nonuniform waves. These waves result from normal fluctuations in the conditions used in forming the board. Other surface variations encountered are pits, dimples and cockles. These latter surface imperfections or variations are usually in the order of about Dill-.005 inch or greater.

In order to obtain a satisfactorily smooth nonhighlighting coating of uniform sLu'face appearance on such a surface, it is necessary to smooth or level out these surface variations without filling in the area between the high caliper points of the board. It has not been found possible to obtain this result with conventional roll coating machines.

In operating the roll coating machine the setscrews I! are manually adjusted for the caliper of the board to be coated (e. g. for boards having a caliper of /8 or inch, etc). Next the board 8 is fed between rolls I and I3. In order to give uniform driving friction both rolls I and I3 are covered with a rubber sleeve 2, roll I is fixedly journaled and roll I3 is yieldably mounted on a spring I6 as indicated by the arrows B. Both rolls I and I3 are driven from the common power source D by the chain drive arrangement shown in Figures 7 and 8 in the direction of the board feed and at a predetermined surface speed which determines the feed of the board through the coating machine. The board is driven between spring mounted resiliently sleeved pressure'roll I4 and the fixedly journaled applicator roll 5 surface grooved at 6 to pick up'and carry enough paint from the paint supply trough 4 to coat the surface I of the board 8 with an excess of paint.

The adjustable relationship (as indicated by arrows A) of doctor roll 9 with respect to applicator roll 5 permits control of the wet paint film applied to the applicator roll. The adjustment of doctor roll 9 is controlled by means of the movable journal box 20 and the adjustable screw 2I Continuing the description of the operation of the roll coating machine, the pressure roll I4 maintains a substantially constant and uniform pressure of the board against the applicator roll 5 and permits good paint coverage of the board surface I. The relative position of the board and the rolls at this stage is very similar to that shown in Figure 3 of the drawing. The pressure roll I i pushes up the thin portion of the board and causes the board to more uniformly contact the applicator roll. The pressure roll I4 and applicator roll 5 are driven in the direction of the board feed and at a surface speed synchronized therewith by means of the gear drive 22 and the chain drive mechanisms 23, 24, and 25 respectively.

Next the coated board is driven between spring mounted resiliently sleeved pressure roll I5 and fixedly journaled hard polished surface wiping roll I I. The wiping roll removes the excess paint from the board andsmooths the ridges in the paint caused by the applicator roll. The direction and surface speed of pressure roll I5 is the same as that of pressure roll I 4. The wiping roll II is driven by the chain drive 26 in a reverse direction to that of the board feed and at a surface speed less than that of the board so that there is always a wedging action on the paint which forces it into and fills up the pits and valleys on the surface of the board and at the same time leaves the high spots (ridges and cockles) relatively bare of paint, because about the only paint remaining on the high spots after this operation is that taken up by the surface of the board at these points. Surface speeds of the wiping roll of A;% the speed of travel of the board have been used with good results. The action of the pressure roll I5 in pushing up the thin portion of the board and causing the board to more uniformly contact the wiping roll is shown in Figures 2 and 3. The doctor blade I2 removes the excess paint from the Wiping roll II and returns (not shown) the paint for re-use.

Other arrows in the drawing not specifically designated indicate the direction of travel of the board and rotation of the rolls.

When operating such that the surface speed of the wiping roll II is about 4- 4 of the speed While this invention has been described with reference to the preferred embodiment thereof and while better results are obtaind by so practicing the invention, the invention is not limited to this embodiment. Instead of springs It for mounting the pressure rolls [3, I 4 and [5, any means can be used provided the pressure rolls are yieldable as pointed out hereinbefore. For example the journal box of the pressure rolls can be mounted on fluid supported pistons or a similar result can be accomplished by use of weighted lever arms and the like as illustrated in Figures 5 and 6, respectively.

The excess coating material may be applied to a sheet material by any suitable conventional means (e. g. by spray, doctor blade, brush, etc.) and then the sheet passed between wiping roll H and pressure roll 15 or their equivalents. However, substantially better results are obtained by applying the excess coating material by means of the preferred embodiment of the coating machine described herein. The coating applied by the present coating machine is usually referred to in the trade as the base coat. Because of the high solids content (normally about 80% solids or greater) used in the coating material for forming the base coat, the alternate methods just listed for applying an excess of coating material of this nature are less desirable than the method described in more detail hereinbefore.

While this invention is particularly applicable to coating rigid sheet materials having the imperfections hereinbefore described (hardboards, wallboards and plywood being examples of this type sheet material), it is also applicable to coating rigid sheet materials in general.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not to be limited to specific embodiments thereof except as defined in the attached claims.

I claim:

1. Apparatus for coating comprising means for applying an excess of coating material to the surface of a rigid sheet material having rough surfaces and nonuniform caliper; a smooth hard polished surface wiping roll fixedly journaled; a work supporting pressure roll opposed to and cooperating with the wiping roll, the axes of the two rolls being substantially parallel and in a plane substantially perpendicular to that surface of the sheet being coated, at least the outer portion of said pressure roll being of a resilient material, yieldable mountings for said pressure roll so that the roll is yieldable in said plane and exerts a substantially constant and uniform pressure on the sheet; and means for removing the excess coating material from the wiping roll.

2. Apparatus for coating comprising means for applying an excess of coating material to the surface of a traveling rigid sheet material having rough surfaces and nonuniform caliper; a smooth hard polished surface wiping roll fixedly journaled to smooth the ridges of coating material and remove the excess coating material from the sheet; means for driving the wiping roll at a predetermined differential surface speed and in a reverse direction relative to that of the sheet; a work supporting pressure roll opposed to and cooperating with the wiping roll, the axes of the two rolls being substantially parallel and in a plane substantially perpendicular to that surface of the sheet being coated, at least the outer por- 8 tion of said pressure roll being of a resilient material, yieldable mountings for said pressure roll so that the roll is yieldable in said plane and exerts a substantially constant and uniform pressure on the sheet; and means for removing the excess coating material from the wiping roll.

3. Apparatus for coating comprising means for app-lying an excess of coating material to the surface of a traveling rigid sheet material having rough surfaces and nonuniform caliper; a. smooth hard polished surface wiping roll fixedly journaled to smooth the ridges of coating material and remove the excess coating material from the sheet; means for driving the wiping roll at a predetermined diiferential surface speed and in a reverse direction relative to that of the sheet; a work supporting pressure roll opposed to and cooperating with the Wiping roll; the axes of the rolls being substantially parallel and in a plane substantially perpendicular to that surface of the sheet being coated, the outer portion of said pressure roll being of a resilient material in the form of a sleeve mounted around a relatively nonresilient core, said pressure roll being journaled in a journal box which in turn is mounted on means including a spring so that the pressure roll is yieldable in said plane and exerts a substantially constant and uniform pressure against the sheet; and means for removing the excess coating material from the wiping roll.

4. The apparatus of claim 3, and in which there is means for manually adjusting the compression of said spring. i

5. Apparatus for coating comprising means for applying an excess of coating material to the surface of a traveling rigid sheet material having rough surfaces and nonuniform caliper; a smooth hard polished surface wiping roll fixedly journaled to smooth the ridges of coating material and remove the excess coating material from the sheet; means for driving the wiping roll at a predetermined differential surface speed and in a reverse direction relative to that of the sheet; a work supporting pressure roll opposed to and cooperating with the wiping roll; the axes of the two rolls beingsubstantially parallel and in a plane substantially perpendicular to that surface of the sheet being coated, the outer portion of said pressure roll being of a resilient material in the form of a sleeve mounted around a relatively non-resilient core, said pressure roll being journaled in a journal box which in turn is mounted on means including a fluid supported piston so that the pressure roll is yieldable in said plane and exerts a substantially constant and uniform pressure against the sheet; and means for removing the excess coating material from the wiping roll.

6. Apparatus for coating comprising means for applying an excess of coating material to the surface of a traveling rigid sheet material having rough surfaces and nonuniform caliper; a smooth hard polished surface wiping roll fixedly journaled to smooth the ridges of coating material and remove the excess coating material from the sheet; means for driving the wiping roll at a predetermined diflerential surface speed and in a reverse direction relative to that of the sheet; a work supporting pressure roll opposed to and cooperating with the Wiping roll, the axes of the two rolls being substantially'parallel and in a plane substantially perependicular to that surface of the sheet being coated, the outer portion of said pressure roll being of a resilient material in the form of a sleeve mounted around a relatively non-resilient core, said pressure roll being journaled in a journal box to which is attached a means including a we1ghted lever member so that the pressure roll is yieldable in said plane and exerts a substantially constant and uniform pressure against the sheet; and means for removing the excess coating material from the wiping roll; a

7. Apparatus for coating the surface of a traveling rigid sheet material having rough surfaces and nonuniform caliper comprising a drive roll, at least the outer portion of which is of a resilient material; coating material supply means; an applicator roll, the peripheral portion of which is adapted to pick up coatingmaterial from the coating material supply means and apply to the surface of the sheet; a doctor roll having its axis parallel to and adjustable with respect to distance from the axis of the applicator roll and controlling the film of coating material onthe 'applicator roll; a smooth hard polished surface wiping roll to smooth the ridges of coating material and remove the excess coating material from the sheet means for driving the wipspeed and in a reverse direction relative to that of the sheet; a doctor blade for removing the coating material from the wiping roll, said driving roll and applicator roll'and wiping roll being roll opposed to and cooperating with each of, said drive roll and applicator roll and wiping roll, the I axis .of each pair of said rolls being substantially parallel and in a plane substantially perpendicue lar to that surface of the sheet being coated, at least the, outer portion of each of said pressure rolls being of a resilient material, yieldable mountings for said pressure rolls so that the rolls are yieldable in said plane and exert a substanfaces and nonuniform caliper comprising an applicatorroll, the peripheral portion of which is adapted to pick up coating material from the coating material supply means and apply to the surface of the sheet; a doctor roll having its axis parallel toand adjustable with respect to distance from the axis of the applicator roll and controlling the film of coating material on the I applicator roll; a smooth hard polished surface wiping roll to smooth the ridges of coating material and remove the excess coating material from the sheet; means for driving the wiping roll at a predetermined differential surface speed and in a reverse direction relative to that of the sheet;

a doctor blade for removing the coating material from the wiping roll, said drivingroll and. applicator roll and wiping roll being fixedly journaled; a worksupporting. pressure roll opposed to and t cooperating with each of said drive roll and applicator roll and wiping roll, the axis of each pair of said rolls being substantially parallel and in a plane substantially perpendicular to that suring roll at a predetermined" difierential surface face of the sheet being coated, at least the outer portion'of each of'said pressure rolls being of a resilient'material, yieldable mountings for said pressure'roll so that the rolls are yieldable in said fixedly 'journaled; a worksupporting pressure tially constant and uniform pressure against the sheet. v

8. Apparatus for coating the surface of a substantially rigid sheet material having rough surplane and exert a substantially constant and uniform pressure against the sheet. 7

EDWIN H. BRINK.

References Cited in the file of this patent V UNITED STATES PATENTS Number Name Date 1,195,219 Hedstrom Aug. 22, 1916 l 2,157,286 Emmey May 9, 1939 2,196,894 Boice Apr. 9, 1940 2,229,831 Adams Jan. 28, 1941 2,282,628 Whann et a1. a May 12, 1942 2,301,619 Davis Nov. 10, 1942 2,354,777

Schwartz Aug. 1, 1944 

